From f63f452ea6846867b7e775dcc0542b94fb9b1369 Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Fri, 22 Jan 2021 18:15:13 +0000 Subject: [PATCH] drm/i915/gem: don't trust the dma_buf->size At least for the time being, we need to limit our object sizes such that the number of pages can fit within a 32b signed int. It looks like we should also apply the same restriction to any imported dma-buf. Signed-off-by: Matthew Auld Reviewed-by: Chris Wilson Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20210122181514.541436-1-matthew.auld@intel.com Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c index 04e9c04545ad..dc11497f830b 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c @@ -244,6 +244,16 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev, } } + /* + * XXX: There is a prevalence of the assumption that we fit the + * object's page count inside a 32bit _signed_ variable. Let's document + * this and catch if we ever need to fix it. In the meantime, if you do + * spot such a local variable, please consider fixing! + */ + + if (dma_buf->size >> PAGE_SHIFT > INT_MAX) + return ERR_PTR(-E2BIG); + /* need to attach */ attach = dma_buf_attach(dma_buf, dev->dev); if (IS_ERR(attach))